• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.13-14
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• 2010

본 논문에서는 경계 모드(Critical Mode) 플라이백 타입의 DC-AC 인버터에 인터리빙을 적용한 디지털 제어를 제안한다. 연속모드(CCM)나 불연속모드(DCM)와 달리 경계 모드의 경우 주파수가 가변되기 때문에 인터리빙으로 구현하기는 상당히 까다로운 측면이 있다. 또한 아날로그 제어기로 구현에 한계를 지니기 때문에 보다 간편한 구현을 위해 디지털 제어IC을 이용하여 구현하는 방법에 대해 기술한다. 본문에서 200W급 플라이백 타입의 DC-AC 인버터에 경계모드 인터리빙을 방법을 적용한 후 실험으로 검증한다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.416-417
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• 2019

In this paper, an effective power flow control strategy (PFCS) based on the centralized control approach and a DC-link (DCV) restoration algorithm for DC microgrid (DCMG) are presented. By investigating the statuses of system power units, eleven operating modes are given to ensure the system power balance under various conditions. To avoid the system power imbalance caused by the delay of grid fault detection, a reliable DCV restoration algorithm is proposed. In the proposed scheme, when an abnormal variation of the DCV is detected, the battery instantly starts a local emergency control mode to restore the DCV to the nominal value regardless of the control mode from the central controller. The simulations and experiments are carried out to prove the effectiveness of the PFCS and the proposed DCV restoration algorithm.

• ETRI Journal
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• v.44 no.5
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• pp.759-768
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• 2022

A novel energy harvesting technique that uses conducted electromagnetic interference as an energy source is presented. Conducted EMI generated from fluorescent light using a switched-mode power supply was measured and modeled as an equivalent voltage source. Two types of rectifier circuits-a bridge rectifier and a voltage doubler-were used as the harvesting devices for conducted EMI source. The matching networks were designed based on the equivalent model, and the harvested power was improved. The implemented energy harvester produces a regulated power over 68.9 mW and current over 15.1 mA while a regulated voltage can be selected between 3.3 V and 5 V. The proposed system shows the highest harvesting power indoor environment and can provide enough power for the Internet of Things devices.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.149-157
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• 2004

We have calculated the power extraction efficiency and the lasing wavelength distribution of complex-coupled(CC) DFB lasers above threshold for various｜$\chi$L｜ and facet reflectivity combinations, and we have compared the results with those at threshold. Also, we have investigated the effect of coupling coefficient ratio(CR) and the reflectivity of AR facet on the power extraction efficiency and the lasing wavelength distribution. At threshold, the single mode yield as a function of power extraction efficiency of in-phase(IP) CC DFB lasers is the same as that of anti-phase(AP) CC DFB lasers. Above threshold, however, the single mode yield as a function of power extraction efficiency of IP CC DFB lasers is much larger than that of AP CC DFB lasers. For IP CC DFB lasers, AR-HR combination has high single mode yield and large power extraction efficiency compared to other facet combinations. IP CC DFB laser with AR-HR combination for ｜$\chi$L｜of 0.8 has the highest single mode yield and largest power extraction efficiency above threshold among the cases considered. For AR-HR combination, as CR increases and the reflectivity of AR facet decreases, both single mode yield and power extraction efficiency increase due to the reduction of the spatial hole burning effect. For AR-HR combination, the lasing wavelength of CC DFB laser has distributed over the stopband of DFB. As CR increases, the lasing wavelength concentrates on the long wavelength side for IP CC DFB laser, while on the short wavelength side for AP CC DFB laser. As ｜$\chi$L｜ increases, the width of the wavelength distribution decreases and the lasing wavelength moves to the long wavelength side.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.651-658
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• 2001

A novel multi-section power divider configuration is proposed to obtain wide-band frequency performance up to microwave frequency region. Design procedures for the proposed microwave broadband power divider are composed of a planar multi-section three-ports hybrid and a waveguide transformer design procedures. The multi-section power divider is based on design theory of the optimum quarter-wave transformer. Furthermore, in order to obtain the broadband isolation performance between the two adjacent output ports, the odd mode equivalent circuit should be matched by using the lossy element such as resistor. The derived design formula for calculating these odd mode matching elements is based on the singly terminated filter design theory. The waveguide transformer section is designed to suppress the propagation of the higher order modes such as waveguide modes due to employing the metallic electric wall. Thus, each section of the designed waveguide transformer should be operated with evanescent mode over the whole design frequency band of the proposed microwave broadband power divider. This paper presents several simulations and experimental results of multi-section power divider to show validity of the proposed microwave broadband power divider configuration. Simulation and experiment show excellent performance of multi section power divider.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.4
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• pp.559-564
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• 2014

A microgrid as a small scale power system is operated by the grid-connected mode and islanded mode. It is anticipated that the battery energy storage system (BESS) is able to be applied to the microgrid for stable power control, such as tie-line and smoothing control in the grid-connected mode and voltage and frequency control in the islanded mode. In this paper, a digital signal processor (DSP), Two BESS controllers based on TMS320F28335 of a microgrid are implemented and are tested to show control performance in the hardware-in-the loop simulation (HILS) system.

• Journal of Power Electronics
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• v.17 no.2
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• pp.464-475
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• 2017

This study examines a P+multi resonant-based voltage control for voltage harmonics compensation under the islanded mode of a microgrid. In islanded mode, the inverter is defined as a voltage source to supply the full local load demand without the connection to the grid. On the other hand, the output voltage waveform is distorted by the negative and zero sequence components and current harmonics due to the unbalanced and nonlinear loads. In this paper, the P+multi resonant controller is used to compensate for the voltage harmonics. The gain tuning method is assessed by the tendency analysis of the controller as the variation of gain. In addition, this study analyzes the slight voltage magnitude drop due to the practical form of the P+multi resonant and proposes a counter method to solve this problem by adding the PI-based voltage restoration method. The proposed P+multi resonant controller to compensate for the voltage harmonics is verified through the PSIM simulation and experimental results.

• Journal of Institute of Convergence Technology
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• v.5 no.1
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• pp.23-26
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• 2015

The purpose of present study is to analysis the Characteristics of fuel economy and Green house gases due to the driving mode conditions of The hybrid electric vehicle(HEV). HEVs are divided into mild and power types according to the their functions. mild type HEVs are inexpensive because they do not need to implement a pure electric mode. Power type HEVs are more expensive but has also better fuel efficiency. In the present paper, the test results for the gasoline vehicle using FTP-75 mode and HWFET are present.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.4
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• pp.359-367
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• 2012

In this paper, the input split type series-parallel hybrid electric vehicle (SPHEV) is established and the interpretation of the dynamic characteristics in four kinds of HEV modes, such as electric vehicle mode, engine mode, hybrid mode, and regeneration mode, is described. For this research, the forward-facing approach simulation method is chosen, which is useful for vehicle dynamic analysis. The rating of each powertrain component is designed based on energy-based concept and electrical peaking hybrid (ELPH) method. Finally, the designed powertrain is evaluated with the developed PSiM simulator and simulation results are shown.

• Journal of Power System Engineering
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• v.4 no.3
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• pp.48-54
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• 2000

This paper describes the effect of molding pressure, specimen geometries for Mixed Mode I/II interlaminar fracture toughness of carbon fiber reinforced plastic composites by using asymmetrical double cantilever beam(ADCB) specimen. The value of $G_{I/IIC}$ as a function of various molding pressure is almost same at 307, 431, 585 kPa. However it shows the highest value under 307 kPa molding pressure. The effect of $G_{I/IIC}$ due to the change of initial crack length of ADCB specimen was almost negligible in this study. It turns out that the condition for mix mode quasi-static crack growth in ADCB specimen is the ratio of the crack length to that of the specimen, i.e., ${\alpha}/L<0.4$.